†This video of Cassandra summit 2012 has mentioned the use of 256 tokens by default (though it's no longer in the conf/cassandra.yaml). I remember that more tokens could lead to more disk seeks or something. I think 256 is an empirical number based on tests of the speaker.†

Here are two more related articles that you want to read.†

On Sat, Jan 5, 2013 at 12:18 AM, Michael Kjellman <> wrote:

From: Alain RODRIGUEZ <>
Reply-To: "" <>
Date: Friday, January 4, 2013 6:00 AM
To: "" <>
Subject: num_tokens - virtual nodes


I just discover the vnodes new feature described here:†

In the post above, Brandon says "If youíd like to upgrade an installation to virtual nodes, thatís possible too, but Iíll save that for a later post". Does this post now exist somewhere ?

From the cassandra.yaml:

# If you already have a cluster with 1 token per node, and wish to migrate to
# multiple tokens per node, see
# num_tokens: 256

I see no reference to vnodes or num_tokens on this wiki.

So, how to switch from "physical" nodes to vnodes ?

This is useful only if your number of nodes is greater than the RF, right ?

Why 256 token by default ? Where this value come from ?

Is there more advantage / disadvantage of using vnodes that improving the internodes data streaming by increasing the number of data sources ?


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